Many Pixel 3 owners are facing a problem that could render their phones unusable. Ars Technica reports that a growing number of Pixel 3 and 3XL owners are experiencing 'bricking', which is when their phones stop responding to commands. The devices are placed in an "Emergency Download Mode" by Qualcomm. This mode won't allow you to install new firmware using regular methods, and you can't access the bootloader to do so.
We don't know what the problem is or how common it is. There's no practical solution other than replacing the phone. We reached out to Google for comments. Ars speculates that there might be a hardware problem like LG's bootlooping. However, there's not enough evidence to prove it.
Regardless, reports of Pixel 3 owners getting bricked aren't good news. Many of these phones are out of warranty, or very close to losing coverage. It is possible that you will have to pay for repairs and a new device. Google extended some Pixel 4 warranties to address known issues, but there is a possibility that the company may do the same and offer free solutions.